1. Field of the Invention
This invention relates generally to a method for recovering entrained liquid from natural gas, and in particular to a method for recovering the entrained liquid in an economical and environmentally attractive manner.
2. Description of Related Art
When fluids are produced from a subterranean formation via a well penetrating the formation, they are commonly stored temporarily in a tank adjacent the well. A portion of the produced fluid is frequently natural gas containing entrained droplets of liquid hydrocarbons, water, and/or brine. The droplets become entrained in the gas either by mechanical action during production or by condensation of a portion of the gas as the temperature decreases during and after production. It is a widespread practice to vent both the gas and the entrained liquid to the atmosphere. In the past, some or all of the entrained liquid was separated from the gas and dumped into unlined earthen pits adjacent the well, thereby wasting a valuable and irreplaceable resource. The dumped liquid then evaporated and/or seeped into the ground, potentially causing severe air, soil, and groundwater contamination. Liquid disposal in unlined pits is now generally prohibited by environmental regulations.
In addition to the gas discussed in the preceding paragraph, produced liquid containing entrained gas is frequently stored in a tank near the well. If the liquid is produced at high pressure, the storage tank must either be capable of withstanding the high pressure or have a large vent. One common approach is to utilize an expensive heavy-walled tank. Another frequent approach is to utilize a galvanized tank, sometimes without a cover. However, it is difficult to detect leaks in galvanized type tanks, and valuable hydrocarbons may be lost to evaporation. Liquid storage tanks are also increasingly subject to environmental regulations, including monitoring for leak detection.
Thus, there is a need for a means of reducing the waste of liquid and gaseous hydrocarbons. Yet another need is to comply with regulations concerning the release of hydrocarbons and brine into the environment. An additional need is to reduce the expenses associated with thick walled storage tanks.
Accordingly, a primary object of the present invention is to reduce waste of liquid and gaseous hydrocarbons.
Yet another object of the present invention is to enable compliance with environmental regulations limiting the release of liquid hydrocarbons and brine into the soil, groundwater, and air.
A further object of the present invention is to allow the use economical thin-walled liquid storage tanks that comply with environmental regulations.